Protective helmet

ABSTRACT

This invention relates to a new and improved helmet comprising an outer shell and an advanced helmet suspension system supported therein. Also provided are adjusting means for fitting the suspension system to the exact head size required, including separate adjustments for the forehead, nape, and top of the head as well as for correctly positioning the suspension system within the shell.

United States Patent 1191 Mirabella 1 Feb. 6, 1973 1541 PROTECTIVE HELMET 3,122,751 3 1964 Jordan ..2 3R 3,500,474 3 1970 A -1' ...2 3R [75] Invent)? M'rabena Hartford 3,513,482 5/1970 H ld n 4.2 31:

- [73] Assignee: Angelica Corporation, St. Louis, FOREIGN PATENTS OR APPLICATIONS 880,682 I 10/1961 Great Britain ..2/3 R Primary Examiner-James R. Boler I Attorney-Rogers, Exell, Eilers & Robbins [57 ABSTRACT This invention relates to a new and improved helmet comprising an outer shell and an advanced helmet suspension system supported therein. Also provided are adjusting means for fitting the suspension system to the exact head size required,including separate adjustments for the forehead, nape, and top of the head as well as for correctly positioning the suspension system within the shell. 1

E8 Claims, 10 Drawing Figures PROTECTIVE HELMET BACKGROUND OF THE INVENTION suspension designs have become more specialized in an effort to optimize the overall performance of the helmet. The resultant designs fall into two basic categories: conformal suspension systems and sling suspension systems.

The conformal systems consist generally of a thick layer of foam or other shock-absorbing medium bonded directly to the inner surface of the helmet shell and molded or configured to fit snugly around the head. The disadvantages of the conformal systems are high cost resulting from the need for multiple basic shell sizes, difficulty in attaining exact fit, high weight, and poor helmet ventilation. The helmet of this invention is not of the conformal type.

The sling suspension system is the other basic category. With the sling system, the weight of the helmet shell is supported through attachment points around the circumference of the shell rather than through pads bonded to its inner surface as with the' conformal system. Slings generally consist of a circumferential sweat band and over-the-head straps, webbing or netting.

The advantages of the sling systems are their size adjustability, light weight, good helmet ventilation, and mechanical flexibility. By mechanical flexibility is meant that the relatively simple design of the sling permits the selection of materials from either fabrics, plastics, or metals depending onthe exact mechanical properties of the system desired. Conversely, with conformal systems, there are relatively few materials which can be used in their construction.

Unfortunately, there are certain disadvantages to the prior art helmet suspension systems which include inadequate adjustment provisions, improper location of suspension members, minimal contact area with the head, and inherent design deficiencies placing the helmet center of gravity too high.

The sling-type helmet suspension system of this invention obviates the problems associated with the prior art systems to provide a helmet design which offers vast improvements in the areas of sizing and fit, comfort, stability, and protection over the prior art.

SUMMARY OF THE INVENTION The advanced helmet suspension system of this invention is of the sling type and includes generally a protective shell of suitable material, such as metal or plastic, supported on the head by a sling suspension assembly. The suspension assembly generally includes a right suspension assembly and a left suspension assembly, each adjustably supported by right and left side mounting brackets, respectively. Each mounting bracket has a base or circumferential strap made to extend from the side of the head forward over the forehead and rearward under the nape of the neck, and two substantially parallel straps extending from the base strap at the side of the head over the top of the head. The forehead, nape and top straps of the right and left suspension assemblies are aligned so that each of these straps of one side suspension assembly overlaps the corresponding strap of the other side suspension assembly with each having appropriate connection means for providing independent size adjustment for the forehead, nape and top of the head. The adjustable nape straps are curved slightly downward to provide a snug fit under the nape of the neck.

The combination of these independent strap adjustments together with the adjustable means for mounting the right and left suspension assemblies to the mounting brackets provide a total adjustment to fit the sling to any size head, as well as to position the sling within the helmet shell as desired by the wearer.

Other features include left and right chin strap yokes and a chin strap and cup assembly. These yokes are adjustably mounted to the left and right mounting brackets, respectively, to provide supports for the chin strap which is adjustably connected to the lower ends of the yokes.

This suspension assembly design includes several unique features. It permitsthe fabrication of the straps from a buildup of materials selected in accordance with the protection requirements'of the helmet. Also the key to achieving stability in suspension system design is to make the diameter of the circumferential strap smaller than the maximum diameter of the head and to locate the plane of the circumferential strap below the plane of the maximum head diameter. This objective is achieved in this advanced helmet suspension system by incorporating an adjustable nape strap as an integral part of the circumferential strap allowing adjustment of the nape strap with the helmet in place.

These and other features of the invention are described in detail in the description to follow.

DESCRIPTION OF THE DRAWINGS:

FIG. 1 is a side elevational view of the helmet of this invention shown in the donned position with the protective shell shown in dashed lines to illustrate the sling suspension assembly therein;

FIG. 2 is a front elevational view of the sling suspension assembly;

FIG. 3 is a left-side elevational view of the sling suspension assembly of FIG. 1 with the right end of the chin strap disconnected;

FIG. 4 is a plan view of the helmet of FIG. 1 on an enlarged scale with the protective shell shown indashed lines to illustrate the sling suspension assembly therein;

FIG. 5 is an enlarged view in section taken along the line 5-5 of FIG. 4; l FIG. 6 is an enlarged view in section taken along the line 6-6'of FIG. 4;

FIG. 7 is an enlarged view in section taken along the line 7-7 of FIG. 4;

FIG. 8 is an inside elevational view of the mounting bracket of this invention;

FIG. 9 is an inside elevational view of the left suspension assembly shown in its flattened position; and

FIG. 10 is an outside elevational view of the right suspension assembly shown in its flattened position.

Referring primarily to FIGS. 1 through 4, there is shown the protective helmet of this invention including generally a protective shell 22 of metal, plastic or other suitable material to provide a protective outer shield, and supporting the shell 22, a sling suspension assembly 24.

The shell 22 is supported by the sling suspension assembly 24 by means of left and right side mounting brackets 26 and 28, respectively, the sling assembly 24 generally including a left suspension assembly 30, a right suspension assembly 32, a left chin strap yoke 34, a right chin strap yoke 36 and a chin strap andcup assembly 38.

The left and right mounting brackets 26 and 28 are identical, and shaped generally as shown in FIGS. 1, 2, 3 and 8, each having keyhole slots 40 and 42 located generally at opposite ends of the bracket. Associated with each keyhole slot are a large aperture portion 43 and narrower slot portion 44 having a recess 45 to receive the head of a mounting pin. The slot portion 44 extends away from the large aperture portion 43 toward the closest end of the mounting bracket. Hence, associated with the keyhole slot 40 are pairs of elongated slots 46, 48 and 50, and associated with the keyhole slot 42 are pairs of elongated slots 52, 54 and 56. As will be described, the purpose of these slots is to adjustably support the remaining portions of the sling assembly.

As best shown in FIGS. 1, 4 and 6, pins and 62 are rigidly secured to the wall of the helmet shell on the left side, and pins 64 and 66 are rigidly secured to the wall of the shell on the right side. Each of the pins 60, 62, 64 and 66 has a shank 69 and a head 70, the head 70 being small enough to pass through the large aperture portion 43 of the appropriate keyhole in the appropriate mounting bracket, but too large to be removed from the keyhole when its shank is located in the keyhole slot 44. i

The keyholes 40 and 42 are spaced such that the distance between their large aperture portions 43 is equal to the distance between the mouhting pins 60 and 62, or 64 and 66 with the mounting brackets held flat.

Holding the mounting brackets in the generally flat position, the mountingbracket 26 is mounted inside the left wall portion of the helmet shell 22 by placing the large aperture portions 43 of the keyholes 40 and 42 over the pins 60 and 62, respectively. Due to forces acting on the mounting brackets by the sling assembly 24, as will be hereinafter explained, the brackets 26 and 28 are caused to curve to the general contour of the head after they are released, in turn causing the thus permitting instant installation and removal of the suspension system from the shell; and additionally through their elastic strength provide support for and maintain the shape of the assembled suspension system.

The left and right side suspension assemblies 30 and 32, respectively, are basically similar as shown in FIGS. 9 and 10. Referring to FIG. 9, the left side suspension assembly 30 generally includes a side strap portion having extending therefrom a nape strap 81, a forehead strap 82, a foretop strap 83, and an aft top strap 84. .The straps 81 through 84 are'curved as shown in the drawing to conform to the contours of the head when the assembly 30 is assembled with the other components of the sling, as will be hereinafter described. Mounting straps 85, 86, 87 and 88 are affixed to the side strap portion 80 by any suitable means such as stitching 89. The mounting straps 85 through 88 are of anysuitable material such as nylon web, and of a width approximately equal to the length of the slots 46, 48, 52 and 54 of the left side mounting bracket 26.

As best shown in FIG. 4, the mounting strap 85 is threaded through the slots 52, the mounting strap 86 is threaded through the slots 54, the mounting strap 87 is threaded through the slots 48, and the mounting strap 88 is threaded through the slots 46.

In like manner, the right side suspension assembly 32 generally includes a side strap portion 90 having extending therefrom a nape strap 91, a forehead strap 92, a foretop strap 93, and an aft top strap 94. The straps 91 through 94 are curved as shown in FIG. 11, just as are the straps 81 through 84 of the left side suspension assembly 30, to conform to the contour of the head. Also, like the left side assembly 30, the right side assembly 32 includes mounting straps 95, 96, 97 and 98 HffiXCditO the side strap portion 90, by stitching 99 or other suitable means, for adjustably attaching the right side assembly 32 to the right side mounting bracket 28. Hence, the mounting strap 95 is threaded through the slots 46, the mounting strap 96 is threaded through the slots 48, the mounting strap 97 is threaded through the slots 54, and the mounting strap 98 is threaded through the slots 52.

As will be described in more detail, the threading of the mounting straps into the slots of. the mounting brackets provides adjustment means for positioning the sling 24 within the helmet shell.

In this describedembodiment, the straps 81 through 84 of the left side suspension assembly 30 are made to overlie the straps 91 through 94, respectively, of the right sidesuspension assembly 32, although, of course, the right side assembly could be made to overlie the left side assembly, if desired.

A pad 100 of pile, such as the pile used in Velcro hook and pile, is attached, such as by stitching, to substantially the full length of the inner surface of each of the straps 81 through 84 of the left side suspension assembly 30, and a pad 101 of tiny hooks, such as those used in Velcro hook and pile, is attached such as by stitching, to substantially the full length of the outer surface of each of the straps 91 through 94 of the right side suspension assembly 32. Wlth the straps 81 through 84 of the left side suspension assembly 30 made to overlie the straps 91 through 94 of the right side suspension assembly 32, the hook pads 101 engage the pile pads 100 to securely attach the right and left assemblies together. The hook and pile provides nearly limitless adjustability between maximum and minimum head sizes. While other forms of connectors could be used, such as a series of snap connectors, none offer the range of size adjustment and ease of connection that the hook and pile provides.

The left and right suspension assemblies are a unique feature of this invention. Because the sling is comprised of left and right members, each of which can be made to lie flat, they can be fabricated from a buildup of materials cut from a pattern. In this manner, the materials may be selected to fit the specific requirements of the sling. For example, as best shown in FIGS. 5 through 7, each of the straps 81 through 84 of the left side assembly 30 includes a double thickness of heavy woven fabric 105 held together by stitching 106. The pile padding 100 is attached to the inside surface of the fabric 105 by appropriate stitching. Each of the straps 91 through 94 of the right side assembly 32 is also comprised of a double thickness of heavy woven fabric 110 with the hook pads sewn on the outside surfaces of the straps. Because the straps of the right side assembly 32 are next to the head, it may be preferable, depending on the shock requirements of the sling, to include between the fabric layers 110 a layer of padding 111 of foam or other suitable padding material. Also, as shown in FIG. 7, a leather sweat band 115 is sewn to the inside surface of the foreheadstrap 92.

As can be seen, this pattern design offers great selectivity in the types of materials and number of layers used in fabricating the sling.

Referring to FIGS. 1, 2 and 3, the left side 'yoke' 34 includes a fore-suspension strap 120 having one end threaded through the slots 56 of the left mounting bracket 26, and an aft suspension strap 121 having one end threaded through the slots 50 of the left mounting bracket 26. The other ends of the straps 120 and 121 are joined by a triangular piece 122 of heavy woven fabric or other suitable material. Because the inside surface of the triangular piece 122 contacts the face, a similar triangular piece 123 of leather or other perspiration-absorbing material is sewn to the inside of the piece 122 with the lower ends of the straps 120 and 121 sandwiched therebetween. A snap connector 124 is mounted in the triangular piece 122.

Referring to FIG. 1, the right side yoke 36 is very.

the other ends of the straps 126 and 127 of the yoke 36 are joined by a triangular piece 128 of heavily woven fabric or other suitable material, except that the end of the suspension strap 127 extends slightly below and beyond the lower edge of the triangular piece 128 and is adapted to support a rectangular ring 130. A similar triangular piece 131 of leather or other perspirationlower end of the left yoke 34 under the chin to the lower end of the right yoke 36. A snap connector 135, that mates with the snap connector 124 mounted on the triangular piece 122, is mounted to the left end of the strip 134 for connection to the lower end of the left yoke 34. At the right end 137 of the strap 134 is a small pile pad 138 sewn to the outer surface of the strap 134. Spaced some distance from the pile pad 138, a hook pad 140 is sewn to the exterior surface of the strap 134.

With the left end of the strap 134 snapped to the lower end of the yoke 34, the strap 134 is held in place under the chin by threading the end 137 outwardly through the ring 130, pulling the strap 134 taut, and folding the end 137 back with the pile pad 138 engaging the appropriate portion of the hook pad 140. The lengths of the pads 138 and 140 and the space therebetween are selected in accordance with the size adjustment requirements.

Also included in the chin strap assembly 38 is a strap 150 which extends across the front of the chin with its ends stitched to form loops 151 and 152 around the strap 134 on either side of the face. The loops 151 and 152 make it possible to adjust the strap 150 by sliding it along the strap 134.

ASSEMBLY, SIZING AND DONNING PROCEDURES As heretofore described, the left and right side suspension assemblies 30 and 32 are attached together preferably by means of hook and pile, such as Velcro hook and pile, to form the basic suspension unit. The unit attaches to each of the suspension mounting brackets 26 and 28 by means of the mounting straps 85, 86, 87, 88, 95, 96, 97 and 98, the mounting brackets 26 and 28 in turn being mounted to the helmet shell 22 by means of keyhole slots 40 and 42 and mounting pins 60, 62, 64 and 66. The chin strap yokes 34 and 36 attach to the mounting brackets '26 and 28 by means of the slots 50 and 56; the chin strap assembly 38 attaches to the yoke assemblies by means of the snap connectors 124 and 135, the rectangular ring 130 and the hook and pile 138 and 140 on the strap 134.

Generally, the helmet height or offset is controlled by adjustment of the fore and aft top straps 83, 84, 93 and 94 made prior to installation of the suspension assembly in the shell; the sling circumference and fore and aft positioning of the sling within the helmet shell is controlled by appropriate positioning of the eight mounting straps through 88 and through 98 in the mounting bracket slots; circumferential tension is controlled by adjustmentof the nape straps8l and 91; and the chin strap length and tensionis controlled by the combined adjustment of the chin strap yokes 34 and 36 in the mounting bracket slots 50 and 56 and the strap 134 in the rectangular ring 130.

INITIAL ASSEMBLY AND SIZING To assemble and size the helmet of this invention, the wearer places the left side suspension assembly 30 on a table in front of him with the pile pads facing up and the nape strap 81 extending to the left. The right side suspension assembly 32 is placed to the right of the left side assembly 30 with the leather sweat band facing up and the nape strap 91 extending to the right. With the left and right suspension assemblies 30 and 32 so positioned, the forehead strap 92 is attached to the forehead strap 82 by overlapping the hook pad 101 of the forehead strap 92 on the pile pad 100 of the forehead strap 82. For most head sizes this overlapping should be such that the hook pad completely overlaps the pile pad. By grasping the nape strap 81 in the left hand and nape strap 91 in the right hand, the nape straps are brought together behind the head with the forehead pressed against the sweat band 115. The circumference of the sling assembly is then adjusted to fit snugly around the head by adjusting the nape straps 81 and 91 just below the back of the head by means of the correct where there is approximately a /4 inch clearance between the ears and the sling. Next the foretop straps 83 and 93 and the aft top straps 84 and 94 are fastened together to fit snugly against the top of the head by means of the hook and pile pad.

With the head straps of the sling correctly adjusted, the sling is removed, the position of each strap marked, and the left and right suspension assemblies 30 and 32 disassembled to facilitate further assembly.

The procedure for attaching the left and right side suspension assemblies 30 and 32 tothe mounting brackets 26 and 28 is basically identical so that only one need be explained in detail.

The same procedure is followed for mounting the left side suspension assembly 30 with the strap 85 corresponding to the strap 95 and threaded through the slots 52; the strap 86 corresponding to the strap 96 and threaded through the slots 54; the strap 87 corresponding to .the strap 97 and threaded through the slots 48; and the strap 88 corresponding to the strap 98 and threaded through the slots 46.

With the left suspension assembly 30 attached to the left mounting bracket 26 by means of the mounting straps 85 through 88, and the right suspension assembly 32 attached to the right mounting bracket 28 by means of the mounting straps 95 through 98, each of the strap 81 through 84 of the left assembly 30 is attached to its corresponding strap 91 through 94 of the right assembly 32 as previously marked. Next, the entire suspension assembly 24 is mounted in the helmet shell The right sling assembly 32 is placed on the table with the mounting straps 95 through 98 facing up and the nape strap 91 extending to the left. The mounting bracket 28 is held above the assembly 32 with the slots 46 directly above the strap 95, the slots 48 above the strap 96, the slots 54 above the strap 97 and the slots 52' above the strap 98. Referring to FIG. 4, the strap 95 is threaded through the slots 46 in the manner shown in the drawing so that the strap 95 is pulled flush with the mounting bracket 28. Next the strap 96 is threaded Head Size Head Circumference Strap 87 or 97 Position Lar e Greater than 23 in. flush with mounting bracket Me ium 22-23 inches 9% inch slack Small Less than 22 in. VI inch' slack Next the strap 98 is threaded through the slots 52'aI- lowing slack in accordance with the head size adjustment desired. The following table gives slack adjustment for eitherthe strap 88 of the left sling assembly 30 or the strap 98 of the. right sling assembly 32 for .large,

medium and small head sizes: 1

Head

Size Head Circumference Strap 88 or 98 Position Large Greater than 23 in. 1 84 inch slack Medium 22-23 inches 5: inch slack A inch slack Small Less than 22 in.

As shown in FIG. 4, the adjustment of the strap 98 causes the mounting bracket to curve.

22 by holding the left and right side mounting brackets 26 and 28 straight and placing the large aperture portions 43 of the keyhole slots 40 and 42 over the pins 60, 62, 66 arid 64. When the mounting brackets are released and allowed to curve as shown in FIG. 4, the narrow slot-portions 44 of the keyhole slots 40 and 42 slide over the shanks of the mounting pins, thereby holding the sling in the shell.

The assembly and sizing procedure heretofore described is meant by way of example only, it being understood that the forehead straps 82 and 92 need not completely overlap, but can be appropriately adjusted just as the other head straps to fit a particular size head. Additionally, the mounting straps can be adjusted to more exact tolerances than set forth in the above tables to fit any size head, and to position the sling assembly 24 up and down or fore and aft in the shell 22.

DONNING PROCEDURE To don the helmet 20, the helmet is held upside down with the front of the helmet toward the body. The nape straps 81 and 91 are separated, the nape strap 81 held open with the thumb of the left hand while grasp- CHIN STRAP ASSEMBLY INSTALLATION AND ADJUSTMENT The chin strap assembly 38 is optional, the helmet being perfectly functional for certain applications, such as protection from falling objects, without the chin strap assembly. However, the chin strap assembly is recommended where impact might jar the helmet from the head.

With the suspension assembly 24 removed from the shell 22, the left yoke 34 is attached to the left mounting bracket 26 by threading the endof the strap through the slots 56 and the end of the strap 121 through the slots 50, and the yoke 36 is attached to the right mounting bracket 28 by threading the strap 126 through the slots 50 and the strap 127 through the slots 56, as best shown in FIGS. 1 and 3. The yokes should be threaded loosely at first until final adjustment is made of the chin strap assembly 38. Next the snap connector 135 of the chin strap assembly 38 is connected to the connector 124 on the left yoke 34. The strap 134 is extended under the chin with the strap 150 positioned over the front of the chin. The end 137 is threaded through the rectangular ring and folded back with the pile pad 138 pressed on the hook pad 140 so that the chin strap assembly is held snugly in place. Exact adjustment of the chin strap is accomplished with the combined adjustment of the straps 120, 121, 126 and 127 of the yokes 34 and 36 and the strap 134 of the chin strap assembly 38.

Various changes and modifications may be made within this invention as will be readily apparent to those skilled in the art. Such changes and modifications are within the scope and teaching of this invention as defined by the claims appended hereto.

What is claimed is:

1. A protective helmet comprising a protective shell, a sling suspension assembly for supporting the shell on the'head, the suspension assembly having a circumferential strap and top straps extending from the circumferential strap over the top of the head, left and right side mounting brackets, means-associated with the left side of the circumferential strap for adjustably mounting the suspension assembly to the left side mounting bracket, means associated with the right side of the circumferential strap for adjustably mounting the suspension assembly to the right side mountirig bracket, the mounting brackets being sufficiently flexible to conform to the general contour of the circumferential strap when mounted thereto, but sufficiently rigid to support and maintain the shape of the suspension assembly, and means for releasably mounting the left and right side mounting brackets to the left and right inside wall portions, respectively, of the shell so that the shell is suspended on the suspension assembly with the inner surface of the shell spaced from the outer surfaces of the suspension assembly.

2. The helmet of claim 1 wherein the left and right side mounting brackets are interchangeable.

3. The helmet of claim 1 wherein the means for adjustably mounting the suspension assembly to the left and right side mounting brackets-includes a plurality of mounting straps attached and spaced along the left and right side portions of the circumferential strap, and for each mounting strap a pair of slots in the mounting bracket adjacent thereto through which the mounting strap is adjustably threaded.

4. The helmet of claim 3 including means associated with the mounting brackets for suspending the shell at four points around the circumference of the shell.

5. The helmet of claim 4 wherein the means for releasably mounting the left and right side mounting brackets to the shell includes a pair of keyhole slots in each mounting bracket, the keyhole slots being at substantially opposite ends of the bracket, each keyhole slot having a large aperture portion and a narrower slot portion extending away from the large aperture portion toward the nearest end of the bracket, a pair of spaced pins mounted to the interior surface at each side of the shell, each pin having a head that passes through the large aperture portion of the keyhole slot but not the narrower slot portion, the location and spacing of the pins being such that the heads of a pin pair pass through the large aperture portions of the associated keyhole pair with the mounting bracket held straight, but remain engaged in the narrower slot portions when the bracket is allowed to curve to the general contour of the circumferential strap, thereby providing a fourpoint quick release mount of the shell on the suspension assembly.

6. The helmet of claim 4 including a chin strap assembly having a strap extending under the chin, with means for supporting one end of the strap from one mounting bracket, and means for adjustably supporting its other end from the other mounting bracket.

7. The helmet of claim 6 wherein the last two named supporting means includes a yoke between each end of the chin strap and the corresponding mounting bracket.

8. A protective helmet comprising a protective shell, a sling suspension assembly for supporting the shell on the head, the sling suspension assembly including a left suspension assembly and a right suspension assembly, each having a side strap portion with a nape strap extending rearwardly therefrom, a forehead strap extending forwardly therefrom, and a plurality of top straps extending upwardly therefrom, mating connector means associated with each of the nape, forehead, and top straps for adjustably attaching each strap of the left suspension assembly to its corresponding strap of the right suspension assembly, and means for suspending the shell on the suspension assembly so that the inner surface of the shell is spaced from the outer surfaces of the suspension assembly.

9. The helmet of claim 8 wherein each of the left and right suspension assemblies are patterned from a buildup of flat sheets of material selected in accordance with the protection requirements of the helmet.

10. The helmet of claim 8 wherein the mating connector means associated with each of the nape, forehead and top straps are hook and pile pads to provide continuous and independent size adjustment over a wide range of sizes for each of the nape, forehead and top straps.

11. The helmet of claim 11 wherein each of the forehead, nape and top straps is curved to fit the contour of the head.

12. The helmet of claim 8 wherein the nape straps are curved downward to fit at the back of the head 1 below the perimeter of maximum circumference of the head, the side straps, forehead straps, and nape straps of the left and right suspension assemblies combining to define a circumferential strap extending around the head, whereby the helmet can be first donned with only the nape straps separated, and then the nape straps adjustably attached in the back of the head, placing the circumferential strap below the head perimeter of maximum circumference.

13. The helmet of claim 8 including quick release means for suspending the shell on the suspension assembly, whereby the suspension assembly can be fitted to the head before the shell is suspended thereon.

14. The helmet of claim 13 including means for suspending the shell at four points spaced around the circumferential strap to provide a stable four-point suspension system.

15. The helmet of claim 8 wherein the means for suspending the shell on the suspension assembly includes means for adjusting the location of the entire suspension assembly in the shell.

16. The helmet of claim 8 including left and right side mounting brackets, means associated with the side strap portion of the left suspension assembly for adjustably mounting the left suspension assembly to the left side mounting bracket, means associated with the side strap portion of the right side suspension assembly for adjustably mounting the right suspension assembly to the right side mounting bracket, the mounting brackets being sufficiently flexible to conform to the general contour of the helmet shell when mounted therein, but sufficiently rigid to support and maintain the shape of the suspension assembly, and means for releasably mounting the left and right side mounting 

1. A protective helmet comprising a protective shell, a sling suspension assembly for supporting the shell on the head, the suspension assembly having a circumferential strap and top straps extending from the circumferential strap over the top of the head, left and right side mounting brackets, means associated with the left side of the circumferential strap for adjustably mounting the suspension assembly to the left side mounting bracket, means associated with the right side of the circumferential strap for adjustably mounting the suspension assembly to the right side mounting bracket, the mounting brackets being sufficiently flexible to conform to the general contour of the circumferential strap when mounted thereto, but sufficiently rigid to support and maintain the shape of the suspension assembly, and means for releasably mounting the left and right side mounting brackets to the left and right inside wall portions, respectively, of the shell so that the shell is suspended on the suspension assembly with the inner surface of the shell spaced from the outer surfaces of the suspension assembly.
 1. A protective helmet comprising a protective shell, a sling suspension assembly for supporting the shell on the head, the suspension assembly having a circumferential strap and top straps extending from the circumferential strap over the top of the head, left and right side mounting brackets, means associated with the left side of the circumferential strap for adjustably mounting the suspension assembly to the left side mounting bracket, means associated with the right side of the circumferential strap for adjustably mounting the suspension assembly to the right side mounting bracket, the mounting brackets being sufficiently flexible to conform to the general contour of the circumferential strap when mounted thereto, but sufficiently rigid to support and maintain the shape of the suspension assembly, and means for releasably mounting the left and right side mounting brackets to the left and right inside wall portions, respectively, of the shell so that the shell is suspended on the suspension assembly with the inner surface of the shell spaced from the outer surfaces of the suspension assembly.
 2. The helmet of claim 1 wherein the left and right side mounting brackets are interchangeable.
 3. The helmet of claim 1 wherein the means for adjustably mounting the suspension assembly to the left and right side mounting brackets includes a plurality of mounting straps attached and spaced along the left and right side portions of the circumferential strap, and for each mounting strap a pair of slots in the mounting bracket adjacent thereto through which the mounting strap is adjustably threaded.
 4. The helmet of claim 3 including means associated with the mounting brackets for suspending the shell at four points around the circumference of the shell.
 5. The helmet of claim 4 wherein the means for releasably mounting the left and right side mounting brackets to the shell includes a pair of keyhole slots in each mounting bracket, the keyhole slots being at substantially opposite ends of the bracket, each keyhole slot having a large aperture portion and a narrower slot portion extending away from the large aperture portion toward the nearest end of the bracket, a pair of spaced pins mounted to the interior surface at each side of the shell, each pin having a head that passes through the large aperture portion of the keyhole slot but not the narrower slot portion, the location and spacing of the pins being such that the heads of a pin pair pass through the large aperture portions of the associated keyhole pair with the mounting bracket held straight, but remain engaged in the narrower slot portions when the bracket is allowed to curve to the general contour of the circumferential strap, thereby providing a four-point quick release mount of the shell on the suspension assembly.
 6. The helmet of claim 4 including a chin strap assembly having a strap extending under the chin, with means for supporting one end of the strap from one mounting bracket, and means for adjustably supporting its other end from the other mounting bracket.
 7. The helmet of claim 6 wherein the last two named supporting means includes a yoke between each end of the chin strap and the corresponding mounting bracket.
 8. A protective helmet comprising a protective shell, a sling suspension assembly for supporting the shell on the head, the sling suspension assembly including a left suspension assembly and a right suspension assembly, each having a side strap portion with a nape strap extending rearwardly therefrom, a forehead strap extending forwardly therefrom, and a plurality of top straps extending upwardly therefrom, mating connector means associated with each of the nape, forehead, and top straps for adjustably attaching each strap of the left suspension assembly to its corresponding strap of the right suspension assembly, and means for suspending the shell on the suspension assembly so that the inner surface of the shell is Spaced from the outer surfaces of the suspension assembly.
 9. The helmet of claim 8 wherein each of the left and right suspension assemblies are patterned from a buildup of flat sheets of material selected in accordance with the protection requirements of the helmet.
 10. The helmet of claim 8 wherein the mating connector means associated with each of the nape, forehead and top straps are hook and pile pads to provide continuous and independent size adjustment over a wide range of sizes for each of the nape, forehead and top straps.
 11. The helmet of claim 11 wherein each of the forehead, nape and top straps is curved to fit the contour of the head.
 12. The helmet of claim 8 wherein the nape straps are curved downward to fit at the back of the head below the perimeter of maximum circumference of the head, the side straps, forehead straps, and nape straps of the left and right suspension assemblies combining to define a circumferential strap extending around the head, whereby the helmet can be first donned with only the nape straps separated, and then the nape straps adjustably attached in the back of the head, placing the circumferential strap below the head perimeter of maximum circumference.
 13. The helmet of claim 8 including quick release means for suspending the shell on the suspension assembly, whereby the suspension assembly can be fitted to the head before the shell is suspended thereon.
 14. The helmet of claim 13 including means for suspending the shell at four points spaced around the circumferential strap to provide a stable four-point suspension system.
 15. The helmet of claim 8 wherein the means for suspending the shell on the suspension assembly includes means for adjusting the location of the entire suspension assembly in the shell.
 16. The helmet of claim 8 including left and right side mounting brackets, means associated with the side strap portion of the left suspension assembly for adjustably mounting the left suspension assembly to the left side mounting bracket, means associated with the side strap portion of the right side suspension assembly for adjustably mounting the right suspension assembly to the right side mounting bracket, the mounting brackets being sufficiently flexible to conform to the general contour of the helmet shell when mounted therein, but sufficiently rigid to support and maintain the shape of the suspension assembly, and means for releasably mounting the left and right side mounting brackets in the left and right inside wall portions, respectively, of the shell so that the shell is suspended on the suspension assembly with the inner surface of the shell spaced from the outer surfaces of the suspension assembly.
 17. The helmet of claim 16 including means associated with the mounting brackets for suspending the shell at four points around the circumference of the shell. 